# CVE-2026-64951: Velociraptor DoS triggered by Divide by Zero panic

> A malicious client can crash the Velociraptor server by uploading a malformed sparse file that triggers a divide-by-zero panic during GUI expansion.

- **Severity:** Low 3.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 12 Aug 2026
- **Updated:** 12 Aug 2026
- **Also known as:** GHSA-frg5-mq2m-h39j

## What is CVE-2026-64951?

CVE-2026-64951 is a low-severity denial of service vulnerability in Rapid7 Velociraptor, published on 12 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

A rogue Velociraptor client can upload a malformed sparse file such that if the GUI attempts to expand the file, a panic occurs which may crash the server process.

The problem is a Divide by Zero bug in the ShouldPadFile() function.

Weakness: CWE-369 (Divide By Zero)

## Which versions are affected by CVE-2026-64951?


## How do I fix CVE-2026-64951?

Apply the vendor's patch.

## Is CVE-2026-64951 being exploited?

There is no known exploitation of CVE-2026-64951 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64951 and fix it if it is affected.

What it is: CVE-2026-64951 is a low-severity denial of service vulnerability in Rapid7 Velociraptor, published on 12 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-64951 in the wild and no public exploit code.

Affected product: Rapid7 Velociraptor. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-64951/ (Markdown: https://insights.sbomify.com/CVE-2026-64951/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64951
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64951
- OSV: https://osv.dev/vulnerability/CVE-2026-64951

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-64951/
Summaries are generated and may contain mistakes; the official description above is the record.